A Quick Guide to- the Goldenrod Crab Spider

The goldenrod crab spider, also known as the flower crab spider, Misumena vatia, captured my attention when I learnt of its colour changing ability. Such an unusual trait for a British spider, I felt it the perfect subject for the next ‘A Quick Guide to’.

The goldenrod crab spider is the only spider from the genus Misumena found in Britian. It is widespread in Southern England, gradually decreasing in abundance towards mid England, being completely absent from North England. It is also widespread in Southern Wales, with only a few small populations in North Wales. It is absent from Scotland.

This species has a varying habitat range but seems to favour boundary edges between grassland and scrub. It is also commonly found in more open areas such as wetlands, grasslands, meadows and gardens, occupying flowers and shrubs. Individuals have been recorded in Britian between May and August but peak times for finding this species are warm, sunny days in May and June.

This spider gets its name due to its resemblance to a crab. It has two pairs of very long front legs, that it holds out to the side like a crab. It also has a large flattened body, adding to this crab-like resemblance.

Females are much larger than males, typically being 9-11mm in length. Males are usually only 3-4mm in length, but their front legs tend to be longer compared to females.

Females are usually white, pale green or yellow depending on background, with one red stripe down each side of the abdomen. These stripes can sometimes apear as large spots or can even be entirely absent. Only mature females can undergo the colour change, which can take a few weeks to have full effect and during the colour change, the red abdominal stripes remain unchanged. They can chage from white to yellow, or vice versa. The change from white to yellow can take some individuals up to a month to complete, yet the change from yellow to white is much quicker, usually only taking a week to complete.

Males are unable to undergo the colour change and their colouration is very different to females. They have a brown thorax with a white or pale green abdomen. The abdomen can also have brown stripes present and individuals can appear quite dark due to this brown colouration.

The colouration of both sexes allow them to camoflague very well against flowers, with the females having a wonderful advantage over other insects due to this fabulous colour changing ability.

The goldenrod crab spider is a hunting spider- rather than spinning a web to catch its prey, it sits and waits on flowers and ambushes insects that come to the flowers to feed. Once the insect is close, it grabs it with its long, very strong, front legs and injects its venom into the prey. This spider favours pollinators such as bees, flies and butterflies and its venom is particularly toxic to bees, allowing to spider to take down large prey.

If you are lucky enough to spot this fascinating spider, take a look to see if it is a light coloured female or a darker coloured male. If it is a female, you may be lucky enough to see her egg guarding. After mating, the female goldenrod crab spider lays her eggs on a leaf, and then folds the leaf over to protect her eggs. She then spins a protective web cocoon around the leaf package and stands guard over the eggs. The eggs usually take around 3 weeks to hatch and during this time the female does not leave them. Shortly after the eggs hatch the female will die, having not fed during the egg guarding process.

Rachel Davies

Currently studying for an MRes in Wildlife Conservation at the University of Chester. Research focuses on the White-faced Darter, an endangered dragonfly species here in Britain.
Rachel also has a blog titled 'working with wildlife'.